I need help with a problem with loading troops onto either Humvee or a Blackhawk

I would really appreciate it if you can help me out with my map making skills with a few questions. I may answer a few days of time due to me being busy but here they are :).

How do you load troops onto vehicles like a Humvee or a Blackhawk?(This is Black hawk down team sabre)

Is there a way your troops can jump into the back of a cargo truck when you get in?(Also in Team Sabre)

Can you help me out with understanding all this? I love building maps but I'm still new here :)

Additional info: This is a Singleplayer map(s) until I'm ready to share my maps with everyone. And this is all on Team Sabre without mods.
I'm sorry if I can't reply quick enough. Thanks for understanding.